Text on video ffmpeg

问题:

How can I add text overlay on my video in ffmpeg?

i.e. given a video "video1.flv", how can I add "StackOverflow" text during the whole video, positioned in the middle of the screen, with white text and a border?

回答1:

Use the drawtext video filter in ffmpeg:

ffmpeg -i input.mp4 -vf drawtext="fontfile=/path/to/font.ttf: \
text='Stack Overflow': fontcolor=white: fontsize=24: box=1: boxcolor=black@0.5: \
boxborderw=5: x=(w-text_w)/2: y=(h-text_h)/2" -codec:a copy output.mp4

• The @0.5 controls the opacity of the text box. In this example it is set to 50%. You can remove @0.5 and there will be no transparency.

• -codec:a copy will stream copy (re-mux) the audio and avoid re-encoding.

• An alternative to the drawtext filter is to use ASS or SRT subtitles–especially if you want timed text or softsubs.

• If you want to update or change the text see the textfile and reload options for this filter.

• This filter requires your ffmpeg to be compiled with --enable-libfreetype. If you get No such filter: 'drawtext' it is probably missing --enable-libfreetype. Most of the ffmpeg static builds available support this, so see the FFmpeg Download page for links.

• See the drawtext filter documentation for more options and examples.